Generally, meters for measuring consumption of electric energy are located in close proximity to the loads consuming the energy, e.g. in a generally accessible area of a home of a subscriber. The control meter is usually installed between a power distribution network and a subscriber line and measures the amount of electric energy drawn via the subscriber line.
Conventionally, authorized personnel manually read counter values of the control meter in predetermined time intervals, with the readings being used for billing subscribers for the consumed electric energy.
To reduce costs associated with reading the meters, techniques have been developed for remote control of the supply of subscribers with electrical energy. General problems of this type have already been described, for example, in Italian patent No. 1 232 195, filed on Oct. 26, 1988 by the present Applicant, or in U.S. Pat. No. 4,803,632.
The approach which these and other different studies have in common can be summarized in an architecture using heterogeneous forms of communication to establish a communication between the peripheral points of the system (meters at the subscriber points), with a supervision center being mainly responsible for the control of the procedures considered in each case to be useful for attaining the objects.
Such a connection is obtained by the direct communication between the supervision center (in general a server with high processor performance) and the peripheral meters, as is described, for example, in WO 98/10299, or by interposing at least one intermediate hierarchical level in this pyramid, as is suggested in WO 98/10394. Examples of these proposals can also be found in other patents such as e.g. EP-A2-0 723 358 or WO 99/46564. The general problem area of remotely controlling the supply of electrical energy is also dealt with in the recent Italian patent application No. MI2001A.002726 as filed on Dec. 20, 2001 in the name of the present applicant
As noted above, meters are generally installed in an area accessible by subscribers and others and therefore it becomes an important issue to avoid fraudulent manipulations to the control meter aiming at drawing electric energy, which is not accounted for.
The most common ways to commit energy fraud require the removal of the metering point, the manipulation of the control meter to alter the measuring constant and/or circumventing the control meter by directly contacting the terminals the mains power supply line.
To counter these attempts of fraud, the technologies known today provide one single system consisting of mounting the apparatus for measuring the energy consumption on a support base which is closed by a lid fixed thereon by means of a seal. The discovery of the break of the seal proves the committed fraud that is then sanctioned according to the facts of the case.
This system has been considered to be sufficient in the past, when it was customary that the control meter was personally controlled and looked at by an operator at least once a month, even if only to read off the consumption. However, this system has proven to be inadequate when the energy supply companies considered the systematic control once a month of all meters in the network to be too costly and carried them out less frequently, for example, by asking each subscriber via telephone about his consumption.
At the current state of the art, which permits, as described in the aforementioned patent application No. MI2001A.002726, to remotely read the consumption and even to control the energy supply in real time, including the initiation and termination thereof, the safety system support based on a seal and the direct control of the control meter does not only become inadequate but it is even totally out of the question to propose such system.
A method and system for sensing removal of a utility meter from its socket is known from U.S. Pat. No. 5,523,559, according to which the removal of a meter can be detected by a tampering detection unit, wherein the tampering detection unit is included entirely within a base or base extension and external to the meter.
Further, a device for maintaining a device housing is known from EP 0 447 615 A1, according to which a sensor detects a position of a closure device for example used in meters for metering electricity, so that it may be detected when a housing is opened and the sensed state may be transmitted to the distributor.